12 Commits

Author SHA1 Message Date
Aaron Ballman
84a3aadf0f Diagnose use of VLAs in C++ by default
Reapplication of 7339c0f782d5c70e0928f8991b0c05338a90c84c with a fix
for a crash involving arrays without a size expression.

Clang supports VLAs in C++ as an extension, but we currently only warn
on their use when you pass -Wvla, -Wvla-extension, or -pedantic.
However, VLAs as they're expressed in C have been considered by WG21
and rejected, are easy to use accidentally to the surprise of users
(e.g., https://ddanilov.me/default-non-standard-features/), and they
have potential security implications beyond constant-size arrays
(https://wiki.sei.cmu.edu/confluence/display/c/ARR32-C.+Ensure+size+arguments+for+variable+length+arrays+are+in+a+valid+range).
C++ users should strongly consider using other functionality such as
std::vector instead.

This seems like sufficiently compelling evidence to warn users about
VLA use by default in C++ modes. This patch enables the -Wvla-extension
diagnostic group in C++ language modes by default, and adds the warning
group to -Wall in GNU++ language modes. The warning is still opt-in in
C language modes, where support for VLAs is somewhat less surprising to
users.

RFC: https://discourse.llvm.org/t/rfc-diagnosing-use-of-vlas-in-c/73109
Fixes https://github.com/llvm/llvm-project/issues/62836
Differential Revision: https://reviews.llvm.org/D156565
2023-10-20 13:10:03 -04:00
Aaron Ballman
f5043f46c0 Revert "Diagnose use of VLAs in C++ by default"
This reverts commit 7339c0f782d5c70e0928f8991b0c05338a90c84c.

Breaks bots:
https://lab.llvm.org/buildbot/#/builders/139/builds/51875
https://lab.llvm.org/buildbot/#/builders/164/builds/45262
2023-10-20 10:00:18 -04:00
Aaron Ballman
7339c0f782 Diagnose use of VLAs in C++ by default
Clang supports VLAs in C++ as an extension, but we currently only warn
on their use when you pass -Wvla, -Wvla-extension, or -pedantic.
However, VLAs as they're expressed in C have been considered by WG21
and rejected, are easy to use accidentally to the surprise of users
(e.g., https://ddanilov.me/default-non-standard-features/), and they
have potential security implications beyond constant-size arrays
(https://wiki.sei.cmu.edu/confluence/display/c/ARR32-C.+Ensure+size+arguments+for+variable+length+arrays+are+in+a+valid+range).
C++ users should strongly consider using other functionality such as
std::vector instead.

This seems like sufficiently compelling evidence to warn users about
VLA use by default in C++ modes. This patch enables the -Wvla-extension
diagnostic group in C++ language modes by default, and adds the warning
group to -Wall in GNU++ language modes. The warning is still opt-in in
C language modes, where support for VLAs is somewhat less surprising to
users.

RFC: https://discourse.llvm.org/t/rfc-diagnosing-use-of-vlas-in-c/73109
Fixes https://github.com/llvm/llvm-project/issues/62836
Differential Revision: https://reviews.llvm.org/D156565
2023-10-20 09:50:21 -04:00
Matt Arsenault
25bc999d1f Intrinsics: Add type overload to stacksave and stackstore
This allows use with non-0 address space stacks. llvm_ptr_ty should
never be used. This could use some more percolation up through mlir,
but this is enough to fix existing tests.

https://reviews.llvm.org/D156666
2023-08-09 18:33:11 -04:00
David Tenty
196c144d0b [clang][CodeGenCXX] Improve handling of itanium ABI member function alignment requirements
The itanium ABI for certain platforms requires a minimum alignments for
member function pointers to reserve certain bits for distinguishing
virtual and non-virtual functions.

Our implementation of this however depends on the alignment of the
function involved, which may however not reflect the true alignment of
function pointers on certain targets for which the alignment is
independent of the function (e.g. AIX). Worse, the 2-byte alignment
we use may be less than the ABI minimum for the target, and in the case
we are using explicit sections will result in invalid codegen.

This patch attempts to correct this situation by considering the target
alignment of function pointers as part of making the decision about
whether we need to adjust the function alignment to conform to the ABI.
Targets which do not provide the function ptr alignment information
will return a value of 1 when queried and will conservatively retain
the old alignment.

Differential Revision: https://reviews.llvm.org/D147184
2023-07-06 10:35:26 -04:00
Dhruva Chakrabarti
1c9ec74e3f [Clang][OpenMP] Insert alloca for kernel args at function entry block instead of the launch point.
If an inlined kernel is called in a loop, the launch point alloca would
lead to increasing stack usage every time the kernel is invoked. This
could make the application run out of stack space and crash. This problem
is fixed by using the alloca insertion point while creating the alloca instruction.

Fixes https://github.com/llvm/llvm-project/issues/60602

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D145820
2023-03-17 16:36:12 -04:00
Johannes Doerfert
16a385ba21 [OpenMP] Modernize the kernel launching interface and APIs
We already created a versioned `__tgt_kernel_arguments` struct but it
was only briefly used and its content was passed in isolation anyway.
This makes it hard to add more information in the future. With this
patch we fully embrace the struct as means to pass information from the
compiler to the plugin as part of a kernel launch.

The patch also extends and renames the struct, bumping the version
number to 2. Version 1 entries are auto-upgraded. This is in preparation
for "bare" kernel launches, per kernel dynamic shared memory, CUDA/HIP
lowering, etc.

The `__tgt_target_kernel_nowait` interface was deprecated as it was
unused. Once we actually implement support for something like that, we
can add an appropriate API.

Note: Only plugins with the `launch_kernel` interface are now supported.
      That means that a new clang won't be able to use an old runtime.
      An old clang can still use the new runtime since the libomptarget
      interface did not change.

Differential Revision: https://reviews.llvm.org/D141232
2023-01-21 11:16:21 -08:00
Jennifer Yu
de14befa77 Remove redundant loads.
It is caused by regenerate captured var value when processing the
has_device_addr, the captured var value has been generated in
GenerateOpenMPCapturedVars and passed as Arg in generateInfoForCapture.
The fix just use Arg instead regenerated just same as is_device_ptr
2022-11-04 15:22:25 -07:00
Nikita Popov
a290f3c8fc [OpenMP] Convert tests to opaque pointers (NFC)
Conversion performed using the script at:
https://gist.github.com/nikic/98357b71fd67756b0f064c9517b62a34

These are only tests where no manual fixup was required.
2022-10-07 14:58:27 +02:00
Jennifer Yu
48ffd40ba2 [Clang][OpenMP] Codegen generation for has_device_addr claues.
This patch add codegen support for the has_device_addr clause. It use
the same logic of is_device_ptr. But passing &var instead pointer to var
to kernal.

Differential Revision: https://reviews.llvm.org/D134268
2022-09-20 21:12:30 -07:00
Ron Lieberman
d5b5289561 revert 684f76643 [Clang][OpenMP] Codegen generation for has_device_addr claues.
breaks amdgpu buildbot
2022-09-20 01:37:27 +00:00
Jennifer Yu
684f766431 [Clang][OpenMP] Codegen generation for has_device_addr claues.
Summary: This patch add codegen support for the has_device_addr clause.  It
use the same logic of is_device_ptr.

Differential Revision: https://reviews.llvm.org/D134186
2022-09-19 16:14:57 -07:00